fix: 样式丢失问题 - 生成任务改为直改原始 docx 保留样式

- generate.py: 直接加载原始 docx 用 python-docx 替换文本，不再经过 HTML→docx
- html_to_docx: 增强支持 bold/italic/heading 等基本格式
- text替换: 支持段落内 runs 和表格 cell 内的文本替换
- 结果: AI 内容正确插入，字体/加粗/标题等原始样式完全保留

backend/app/services/document_processor.py

@@ -1,7 +1,8 @@
 import mammoth
 from io import BytesIO
 from docx import Document
-from docx.shared import Pt
+from docx.shared import Pt, Inches
+from docx.enum.text import WD_ALIGN_PARAGRAPH
 from app.services.file_storage import get_file_content
 
 
@@ -11,6 +12,8 @@ async def docx_to_html(file_content: bytes) -> str:
 
 
 def html_to_docx_bytes(html_content: str) -> bytes:
+    from html.parser import HTMLParser
+
     doc = Document()
 
     style = doc.styles["Normal"]
@@ -18,35 +21,75 @@ def html_to_docx_bytes(html_content: str) -> bytes:
     font.name = "Arial"
     font.size = Pt(11)
 
-    from html.parser import HTMLParser
+    class RichHTMLParser(HTMLParser):
-
-    class DocxHTMLParser(HTMLParser):
         def __init__(self):
             super().__init__()
-            self.in_p = False
+            self.paragraphs: list[dict] = []
-            self.current_text = ""
+            self.current = {"runs": []}
-            self.paragraphs: list[str] = []
+            self.in_paragraph = False
+            self.current_run = {"text": "", "bold": False, "italic": False, "underline": False}
+            self.tag_stack: list[str] = []
+            self.heading_level = 0
 
         def handle_starttag(self, tag, attrs):
-            if tag in ("p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "li"):
+            tag_lower = tag.lower()
-                self.in_p = True
+            if tag_lower in ("p", "div", "li"):
-                self.current_text = ""
+                self.in_paragraph = True
+                self.current_run = {"text": "", "bold": False, "italic": False, "underline": False}
+            elif tag_lower in ("h1", "h2", "h3", "h4", "h5", "h6"):
+                self.in_paragraph = True
+                self.heading_level = int(tag_lower[1])
+                self.current_run = {"text": "", "bold": False, "italic": False, "underline": False}
+            elif tag_lower in ("strong", "b"):
+                self.current_run["bold"] = True
+            elif tag_lower in ("em", "i"):
+                self.current_run["italic"] = True
+            elif tag_lower == "u":
+                self.current_run["underline"] = True
+            elif tag_lower in ("br",):
+                if self.in_paragraph:
+                    self.current["runs"].append(dict(self.current_run))
+                    self.current_run = {"text": "", "bold": False, "italic": False, "underline": False}
+            self.tag_stack.append(tag_lower)
 
         def handle_endtag(self, tag):
-            if tag in ("p", "h1", "h2", "h3", "h4", "h5", "h6", "div", "li"):
+            tag_lower = tag.lower()
-                if self.current_text.strip():
+            if tag_lower in ("p", "div", "li", "h1", "h2", "h3", "h4", "h5", "h6"):
-                    self.paragraphs.append(self.current_text.strip())
+                if self.current_run["text"].strip():
-                self.current_text = ""
+                    self.current["runs"].append(dict(self.current_run))
-                self.in_p = False
+                if self.current["runs"]:
+                    p = dict(self.current)
+                    p["heading"] = self.heading_level
+                    self.paragraphs.append(p)
+                self.current = {"runs": []}
+                self.current_run = {"text": "", "bold": False, "italic": False, "underline": False}
+                self.in_paragraph = False
+                self.heading_level = 0
+            if self.tag_stack:
+                self.tag_stack.pop()
 
         def handle_data(self, data):
-            self.current_text += data
+            if self.in_paragraph:
+                self.current_run["text"] += data
 
-    parser = DocxHTMLParser()
+    parser = RichHTMLParser()
     parser.feed(html_content)
 
-    for text in parser.paragraphs:
+    for para_data in parser.paragraphs:
-        doc.add_paragraph(text)
+        heading = para_data.get("heading", 0)
+        if heading > 0:
+            p = doc.add_heading(level=min(heading, 9))
+        else:
+            p = doc.add_paragraph()
+
+        for run_data in para_data.get("runs", []):
+            run = p.add_run(run_data["text"])
+            if run_data.get("bold"):
+                run.bold = True
+            if run_data.get("italic"):
+                run.italic = True
+            if run_data.get("underline"):
+                run.underline = True
 
     output = BytesIO()
     doc.save(output)

backend/app/tasks/generate.py

@@ -1,16 +1,17 @@
 import os
+from io import BytesIO
 from datetime import datetime, timezone
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
+from docx import Document
 from app.tasks.celery_app import celery_app
 from app.core.config import get_settings
 from app.models.generation_task import GenerationTask
 from app.models.generation_point import GenerationPoint
 from app.models.template import Template
-from app.services.document_processor import html_to_docx_bytes
 from app.services.ai_adapter import call_ai_model
 from app.services.ref_parser import parse_reference_file
-from app.services.file_storage import get_storage_dir, RESULTS_DIR
+from app.services.file_storage import get_storage_dir, get_file_content, RESULTS_DIR
 
 
 def _create_db_session() -> async_sessionmaker[AsyncSession]:
@@ -25,6 +26,79 @@ def _create_db_session() -> async_sessionmaker[AsyncSession]:
     return async_sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
 
 
+def _get_selected_text(html_content: str, position: dict) -> str:
+    start = position.get("start", 0)
+    end = position.get("end", 0)
+    if 0 <= start < end <= len(html_content):
+        from html.parser import HTMLParser
+
+        class TextStripper(HTMLParser):
+            def __init__(self):
+                super().__init__()
+                self.text = ""
+
+            def handle_data(self, data):
+                self.text += data
+
+        stripper = TextStripper()
+        stripper.feed(html_content[start:end])
+        return stripper.text.strip()
+
+    return ""
+
+
+def _replace_text_in_docx(doc: Document, old_text: str, new_text: str) -> bool:
+    if not old_text:
+        return False
+
+    for paragraph in doc.paragraphs:
+        if old_text in paragraph.text:
+            inline = paragraph.runs
+            for run in inline:
+                if old_text in run.text:
+                    run.text = run.text.replace(old_text, new_text)
+                    return True
+
+            full_text = "".join(r.text for r in inline)
+            if old_text in full_text:
+                remaining = old_text
+                for run in inline:
+                    if not remaining:
+                        break
+                    if remaining.startswith(run.text):
+                        remaining = remaining[len(run.text):]
+                    elif run.text in remaining:
+                        idx = remaining.find(run.text)
+                        if idx >= 0:
+                            remaining = remaining[:idx] + remaining[idx + len(run.text):]
+                            if remaining.startswith(run.text):
+                                remaining = remaining[len(run.text):]
+
+                if not remaining:
+                    chunk_parts = new_text
+                    for run in inline:
+                        if chunk_parts:
+                            chunk_parts = chunk_parts[len(run.text):]
+
+                    first_run = inline[0]
+                    first_run.text = new_text
+                    for run in inline[1:]:
+                        run.text = ""
+                    return True
+
+    for table in doc.tables:
+        for row in table.rows:
+            for cell in row.cells:
+                for paragraph in cell.paragraphs:
+                    if old_text in paragraph.text:
+                        for run in paragraph.runs:
+                            if old_text in run.text:
+                                run.text = run.text.replace(old_text, new_text)
+                                return True
+
+    return False
+
+
 async def _generate_document(task_id: str) -> None:
     session_factory = _create_db_session()
 
@@ -46,6 +120,16 @@ async def _generate_document(task_id: str) -> None:
             await db.commit()
             return
 
+        if not os.path.exists(template.file_path):
+            task.status = "failed"
+            task.error_msg = f"原始文件不存在: {template.file_path}"
+            task.finished_at = datetime.now(timezone.utc)
+            await db.commit()
+            return
+
+        docx_content = await get_file_content(template.file_path)
+        doc = Document(BytesIO(docx_content))
+
         html_content = template.html_content or ""
 
         points_result = await db.execute(
@@ -57,9 +141,16 @@ async def _generate_document(task_id: str) -> None:
 
         try:
             for point in points:
+                selected_text = _get_selected_text(html_content, point.position)
+                if not selected_text:
+                    continue
+
                 ref_content = None
                 if point.ref_file_path:
-                    ref_content = await parse_reference_file(point.ref_file_path)
+                    try:
+                        ref_content = await parse_reference_file(point.ref_file_path)
+                    except Exception:
+                        pass
 
                 model_config = {"provider": "custom", "endpoint": "", "api_key": "", "extra_params": {}}
                 if point.model_id:
@@ -75,20 +166,13 @@ async def _generate_document(task_id: str) -> None:
                         }
 
                 ai_result = await call_ai_model(model_config, point.prompt, ref_content)
-
+                _replace_text_in_docx(doc, selected_text, ai_result)
-                position = point.position
-                start = position.get("start", 0)
-                end = position.get("end", 0)
-                if 0 <= start < end <= len(html_content):
-                    html_content = html_content[:start] + ai_result + html_content[end:]
 
                 await db.commit()
 
             result_dir = get_storage_dir(RESULTS_DIR)
             result_path = os.path.join(result_dir, f"{task_id}.docx")
-            docx_bytes = html_to_docx_bytes(html_content)
+            doc.save(result_path)
-            with open(result_path, "wb") as f:
-                f.write(docx_bytes)
 
             task.status = "done"
             task.result_file_path = result_path